A) Field of the Invention
The present invention relates to a vacuum processing system, and more particularly to a vacuum processing system having at least two load-lock mechanisms for carrying a process object into and out of a vacuum chamber.
B) Description of the Related Art
A conventional wafer carrying method will be described by taking as an example an ion implanter. JPA HEI 3-29258 (JPB HEI 7-54688) discloses an ion implanter having a vacuum chamber installed with two load-lock chambers. A wafer is carried in and out via the load-lock chambers.
For carrying wafers, first a robot arm picks up a processed wafer from the load-lock chamber and carries it to a wafer stock area. Thereafter, a new wafer still not processed is picked up from a wafer stock area and once placed on an aligner to adjust the posture of the wafer (position alignment based upon a notch or an orientation flat). Thereafter, the robot arm carries the wafer from the aligner into the load-lock chamber.
Since two load-lock chambers are used, a wafer carrying process can be speeded up.
In a conventional ion implanter, the time taken to carry a wafer into and out of a load-lock chamber and taken to the wafer to another location is longer than the time taken actually to implant ions into the wafer.